                                              {:types :raw}))))
         (is (false? (execute-xquery session "fn:doc-available(\"derp\")" {:shape :single!}))) 
         (is (= "xs:boolean"
-               (result->type (execute-xquery session "xdmp:exists(collection())"
+               (result->type (execute-xquery session "fn:true()"
                                              {:types :raw}))))
-        (is (true? (execute-xquery session "xdmp:exists(collection())" {:shape :single!})))))
+        (is (true? (execute-xquery session "fn:true()" {:shape :single!})))))
 
     (testing "......XSDate"
       (with-open [session (create-session db)]


;; (comment
;;   (session->map (create-session {:uri "xdbc://localhost:8383/"
;;                                     :user "rest-admin" :password "x"
;;                                     :content-base "TutorialDB"}
;;                                    {} (uri-content-source "xdbc://localhost:8383/"
;;                                                           (security-options TODO)))))

        (is (= "binary()"
               (result->type (with-open [session (create-session db)]
                               (execute-xquery session (str "xquery version \"1.0-ml\";
                                                             xdmp:external-binary(\""
                                                            path-to-img "\");")
                                               {:types :raw})))))
        (is (= (Class/forName "[B")
